conio.h

Console versions of common I/O functions. They bypass the stdin and stdout buffers and access the console directly.

Function	Description
_kbhit	Determines if a keyboard key was pressed.
_ungetch	Puts a character back into the keyboard buffer.
_getch	Reads a character directly from the console, without echo.
_getche	Reads a character directly from the console, with echo.
_putch	Writes a character directly to the console.
_cgets	Gets a string directly from the console.
_cprintf	Formats and prints a string directly to the console.
_cputs	Outputs a string directly to the console.
_cscanf	Reads and formats values directly from the console.

_kbhit

Header

conio.h
stdio.h

Prototype

int _kbhit(void); int kbhit(void);

Description

Checks if a keyboard key has been pressed but not yet read.

Return Value

Returns a non-zero value if a key was pressed. Otherwise, returns 0.

Compatibility

DOS, Windows 3.x, Phar Lap, DOSX, Win32

See Also

_getch _getche

Example

/* Example of _kbhit() */

#include <stdio.h>
#include <conio.h>
#include <stdlib.h>

int main()
{
 printf("Hit any character key when ready\n");
 while (!_kbhit())
    ;
 printf("\nThe key pressed was (%c)\n", _getch());
 return 0;
}

Output

Hit any character key when ready

The key pressed was (b)

_ungetch

Header

conio.h

Prototype

int _ungetch(int c); int ungetch(int c);

Description

_ungetch function puts the character c back into keyboard buffer, so that c will be the next character read by _getch or _getche. _ungetch can be called only once before the next read.

Return Value

Returns c if successful. If unsuccessful, EOF is returned.

Compatibility

DOS, Windows 3.x, Phar Lap, DOSX, Win32

See Also

_getch _getche ungetc

Example

/* Example for _ungetch */

#include <stdio.h>
#include <conio.h>
#include <string.h>
#include <ctype.h>

int main()
{
   int i = 0;
   char c;
   char str[128];
   printf("Enter an integer: ");
   while ((c = _getche()) != EOF && isdigit(c))
      i = (i * 10) + (c - 48);

   if ((c != EOF) && (c != '\r'))
      ungetch(c);

   if (c != '\r')
   {
     gets(str);
     printf("The integer is %d, and the rest is \"%s\"\n",
            i, str);
   }
   else
      printf("\nThe integer is %d", i);
   return 0;
}

Output

Enter an integer: 80 men are in a Roman Century
The integer is 80, and the rest is "men are in a Roman Century"

_getch

Header

conio.h
stdio.h

Prototype

int _getch(void);

Description

_getch obtains a character from stdin. Input is unbuffered, and this routine will return as soon as a character is available without waiting for a carriage return. The character is not echoed to stdout. _getch bypasses the normal buffering done by getchar and getc. ungetc cannot be used with _getch.

Synonym

Function: getch

Return Value

Returns the next character read and extended character codes, but never returns an error.

Compatibility

DOS Windows 3.x Phar Lap DOSX Win32

See Also

getc getchar _getche putchar

Example

/* Example for _getch */

#include <stdio.h>
#include <stdlib.h>

int main()
{
  int input;

  printf(" Press charcter key...");
  input = _getch();
  printf("\n'%c' was returned by _getch()\n",
         input);
  return 0;
}

Output

Press charcter key...
'g' was returned by _getch()

_getche

Header

conio.h
stdio.h

Prototype

int _getche(void);

Description

The _getche function is the same as _getch except that the character being read is echoed to stdout. Like _getch, it bypass normal buffering done by getchar and getc. ungetc cannot be used with _getche.

Synonym

Function: getche

Return Value

Returns the next character read but never returns an error.

Compatibility

DOS Windows 3.x Phar Lap DOSX Win32

See Also

getc getchar _getch getchar putc stdout

Example

/* Example for _getche */

#include <stdio.h>
#include <stdlib.h>

int main()
{
  int input;

  printf("Input a character: ");
  input = _getche();
  printf("\n'%c' was returned by _getche()\n",
         input);
  return 0;
}

Output

Input a character: g
'g' was returned by _getche()

_putch

Header

conio.h

Prototype

int _putch(int c);

Description

The _putch function writes character c to the console, without buffering.

Synonym

Function: putch

Return Value

If successful, returns c. Otherwise, returns EOF.

Compatibility

DOS Windows 3.x Phar Lap DOSX Win32

See Also

_cprintf _getch _getche

Example

/* Example of _putch */

#include <stdio.h>
#include <conio.h>

int main()
{
  char ch = 0;
  printf(" Input a string: ");
  while ((ch != '\r'))
  {
     ch = _getch();
     _putch(ch);
  }
  return 0;
}

Output

Input a string: The quick brown fox jumped over the lazy dog.

_cgets

Header

conio.h

Prototype

char *_cgets(char *buffer);

Description

The _cgets function gets a character string from the console and stores it in the character array pointed to by buffer. The array's first element, buffer[0], must contain the maximum length, in characters, of the string to be read. The array's second element, buffer[1], is where _cgets stores the string's actual length _cgets reads characters until it reads the carriage-return/ line-feed combination or the specifed maximum number of characters.

Return Value

A pointer to the start of the string at buffer[2]. Returns no error.

Compatibility

DOS Windows 3.x Phar Lap DOSX Win32

See Also

_getch _getche _cprintf

Example

/* Example for _cgets
   Also demonstrates _cprintf

    _CGETS.C
*/

#include <conio.h>

int main()
{
   char buffer[22], *return_value;

   buffer[0] = sizeof(buffer) - 2;
   _cprintf("Type something: ");
   return_value = _cgets(buffer);
   _cprintf("\n\rsize = %d\n\rbuffer = '%s'\n\rreturn value = '%s'\n\r",
      buffer[1],
      buffer + 2,
      return_value);
   return 0;
}

Output

C:\dm\examples>_cgets
Type something: This is something
size = 17
buffer = 'This is something'
return value = 'This is something'

_cprintf

Header

conio.h

Prototype

int _cprintf(const char *format, arg0,... argn);

Description

The _cfprint function writes formatted output to the console, using the function _putch to output the characters. The format argument points to a null-terminated string describing how to format the characters. The formatting commands for converting the text to output are described in the fprintf function listing. Optional arguments describe additional formatting information.

Return Value

The number of characters printed.

Compatibility

DOS Windows 3.x Phar Lap DOSX Win32

See Also

fprintf _putch _cscanf

Example

/* Example for _cprintf

   _CPRINTF.C
*/

#include <conio.h>

int main()
{
  _cprintf("1. \\n works different for console I/O, it goes down:\n");
  _getch();
  _cprintf("2. \\r goes back:\r");
  _getch();
  _cprintf("3. \\r\\n goes down and back:\r\n");
  _getch();
  _cprintf("4. Like this.");
   return 0;
}

Output

C:\dm\examples>_cprintf
1. \n works different for console I/O, it goes down:
3. \r\n goes down and
back:                         2. \r goes back:
4. Like this.

_cputs

Header

conio.h

Prototype

int _cputs(const char *string);

Description

The _cputs function writes a null-terminated string to the console.

Return Value

0 if successful; non-zero if unsuccessful.

Compatibility

DOS Windows 3.x Phar Lap DOSX Win32

See Also

_putch

Example

/* Example for _cputs.c
   SAY.C
*/

#include <conio.h>

int main(int argc, char *argv[])
{
   int i;

   for (i = 1; i < argc; i += 1)
   {
      _cputs(argv[i]);
      _cputs(" ");
   }
   return 0;
}

Output

C:\dm\examples> say Hello World!
Hello World!

_cscanf

Header

conio.h

Prototype

int _cscanf(char *format, arg0,... argn);

Description

The _cscanf function reads input text directly from the console using the _getche function to read the characters. The format argument points to a null-terminated string that describes how to convert the input. The format for converting the input is described in the fscanf function.

Return Value

The number of fields converted and assigned.

Compatibility

DOS Windows 3.x Phar Lap DOSX Win32

See Also

_cprintf fscanf _getche scanf

Example

/* Example for _cscanf and _cprintf
*/

#include <conio.h>

int main()
{
  int a_number;
  char a_string[20];

  _cprintf("Enter a number, then a string\n\r");
  _cscanf("%d %s", &a_number, a_string);
  _cprintf("\nThe number was %d, the string was '%s'\n",
       a_number, a_string);
  return 0;
}

Output

Enter a number, then a string
1492 Ambidexterous
The number was 1492, the string was
'Ambidexterous'

Standard C

Standard C++

Win32

DOS, DOS32, Win16

Other C

Other C++

conio.h

_kbhit

_ungetch

_getch

_getche

_putch

_cgets

_cprintf

_cputs

_cscanf